O’Melveny Worldwide

Sean Trainor is a seasoned litigator who focuses primarily on patent litigation before the US International Trade Commission (ITC). Sean’s experience spans all phases of litigation and a broad range of technologies, including wireless telecommunications protocols, mobile telephone handsets and chipsets, lithium-ion batteries, data storage systems, laser printers and laser toner cartridges, flash memory, semiconductor devices and fabrication, advanced medical devices, laser diodes, and light emitting devices, among others. Sean has particular expertise proving and disproving the domestic industry jurisdictional requirement, unique to ITC investigations.

Sean has been recognized as a leading patent litigator in IAM Patent 1000 (2014-2023).

Get to Know Sean

Get to Know Sean

  • Successfully represented complainants in Certain Lithium Metal Oxide Cathode Materials, Lithium-Ion Batteries for Power Tool Products Containing Same, and Power Tool Products With Lithium-Ion Batteries Containing Same, ITC Investigation No. 337-TA-951, at the US International Trade Commission. The ITC issued a Limited Exclusion Order barring the importation of respondents’ infringing NMC lithium oxide cathode materials after conducting its first oral hearing in a Section 337 case in a decade.
  • Successfully represented respondent in Certain Consumer Electronics and Display Devices with Graphics Processing and Graphics Processing Units Therein, ITC Investigation No. 337-TA-932 at the US International Trade Commission. Obtained complete victory in an investigation that started with seven patents and more than 100 claims in which the complainant sought to exclude all of the respondent’s smartphones and tablets.
  • Represented respondent and several of its customers in Certain Flash Memory Chips and Products Containing the Same, ITC Investigation No. 337-TA-664 at the International Trade Commission. Obtained complete victory in four-patent case in which complaint sought to exclude all of respondent’s flash memory product and dozens of respondent’s and its customers’ downstream products containing respondent’s flash memory. 
  • Represented third-party defendant on behalf of the United States Postal Service in Uship Intellectual Properties, LLC v. United States in the US Court of Federal Claims. Obtained summary judgment of noninfringement on all patents and claims. The US Court of Appeals for the Federal Circuit affirmed the lower court’s summary judgment.  
  • Successfully represented plaintiff pharmaceutical manufacturer in GSK and Tafas v. Dudas and US Patent and Trademark Office in the US District Court for the Eastern District of Virginia. Obtained summary judgment before the district court that the PTO’s rules exceeded their agency authority. Recognized as US Patent Case of the Year 2009 by Managing Intellectual Property.
  • Successfully represented complainant in Certain Systems for Detecting and Removing Viruses or Worms, Components Thereof, and Products Containing Same, ITC Investigation No. 337-TA-510; obtained Limited Exclusion Orders and Cease and Desist Orders; case settled very favorably shortly before hearing in the ensuing enforcement proceeding.


Bar Admissions

  • District of Columbia
  • Virginia

Court Admissions

  • US District Court, Eastern District of Michigan, and Eastern District of Virginia
  • US Court of Appeals, Fourth and Federal Circuits
  • US Court of Federal Claims

Registered to Practice

  • US Patent & Trademark Office


  • George Washington University, J.D., 1998: Managing Editor, George Washington Journal of International Law & Economics, with honors
  • Michigan State University, B.S., Mechanical Engineering, 1995, with honors

Honors & Awards

  • Recognized by Chambers USA in International Trade: Intellectual Property (Section 337) (2021-2024)
  • Recommended by The Legal 500 US for Patents: Litigation (Full Coverage) and Patents: Litigation (International Trade Commission) (2024)
  • Recognized by Chambers Global: USA Region in International Trade: Intellectual Property (Section 337) (2023)
  • Named a “Leading Lawyer” by The Legal 500 US for Antitrust: Cartel (2023)
  • Recognized as a leading patent litigator in IAM Patent 1000 (2014-2023)
  • Recommended by The Legal 500 US for Trademarks: Litigation (2018)

Professional Activities


  • International Trade Commission Trial Lawyers Association 


  • “Enforcement By CBP: Exclusion Orders, Counterfeiting, and Trademark,” Federal Circuit Bar Association, 2020 Bench & Bar® Virtual Conference (June 16, 2020)
  • “Inside The Changing Nuances of Domestic Industry: What the Latest Developments Reveal about Establishing DI,” American Conference Institute: ITC Litigation & Enforcement (March 2018)